Unfortunately the one thing we’re not allowed to do here is give you personal financial advice. Only a qualified and registered financial advisor can do that. Have a look at the “Credit Cards” section of this website and, with the help of a financial advisor if necessary, decide for yourself which card is best for you.
I’d be interested to know what you mean when you say that the AmEx Membership Rewards programme is “dying out”. I haven’t heard anything like that. My personal opinion is that AmEx Membership Rewards is one of the best flexible rewards programmes out there. But again, only you can decide what card is best for you.